The Meta-Object Facility (MOF) Specification (Object Management Group standard) defines an abstract language and a framework for specifying, constructing, and managing technology neutral metamodels. A metamodel can be characterized as an abstract language for some kind of metadata. In addition, the MOF defines a framework for implementing repositories that hold metadata (e.g., models) described by the metamodels. This framework uses standard technology mappings to transform MOF metamodels into metadata APIs. This arrangement gives consistent and interoperable metadata repository APIs for different vendor product and different implementation technologies.
For infrastructures adopting an MOF repository, such as the SAP Modeling Infrastructure (MOIN) in which a declarative query language has been developed (MQL), MOIN is hosted on a database, either centrally (server-based) or locally (client Integrated Development Environment). In such arrangements, current data is maintained in memory, in particular when it is being processed or modified. Data being processed is referred to as “dirty” when it only exists transiently (i.e., until it is saved to a database).
One conventional technique for accessing a MOIN repository is via a standardized JAVA API. With this technique, data must be brought into memory, which unnecessarily consumes memory, especially when large amounts of data must be processed.